Frequently email addresses used in Canvas bounce emails while admin are completely unaware this is happening.
people start using other email addresses and close the previous one
people change email addresses because their name changed because of marriage
people change jobs, the old address is terminated and a new one created
the university disables the university student email account for inactive students
new mail is rejected because the mailbox completely full
Currently Canvas does not (yet) offer a way to proactively identify these problems, while teachers assume all their students receive notifications of e.g. announcements, assignments, etc. as configured in the notification settings.
Let Canvas keep a record of every bounce email returned when sending notification emails to users, containing the data: